PetaPixel

Each month, NPR issues listeners an Instagram photo assignment that has them documenting some small part of their day. The most recent assignment asked participants to document their commute, “that perfectly average and ordinary part of the day that many of us share.”

But this month’s assignment turned into something extra special, when a photo of a mother reading to her son on the subway went viral, touching the lives of many readers and, it turns out, the mother herself.